Investigation of ground-motion spatial variability effects on component and system vulnerability of a floating cable-stayed bridge

2019 ◽  
Vol 22 (8) ◽  
pp. 1923-1937 ◽  
Author(s):  
Kai Ma ◽  
Jian Zhong ◽  
Ruiwei Feng ◽  
Wancheng Yuan
Keyword(s):  
Spatial Variability ◽  
Ground Motion ◽  
Seismic Vulnerability ◽  
Site Response ◽  
Soil Condition ◽  
System Level ◽  
Soil Conditions ◽  
Cable Stayed Bridge ◽  
Wave Passage ◽  
Spatially Varying

The effects of ground-motion spatial variability on the seismic vulnerability of a floating cable-stayed bridge with 420-m long main span are investigated using component and system-level fragility analysis methods. Four combinations of the spatial variability components are considered including (a) the incoherence effect; (b) the incoherence and wave-passage effects; (c) the incoherence and site-response effects; and (d) general excitation case including the incoherence, wave-passage, and site-response effects. Parametric study was carried out to assess the sensitivity of seismic fragility to the variation of spatial variability components. The results indicate that the bridge becomes more vulnerable under spatially varying excitations than uniform excitations. The fragile components and the bridge system become more vulnerable with an increase in incoherence level. The component and system-level vulnerabilities are not sensitive to the variation of apparent wave velocities in most cases. However, the site-response effect is more complex than incoherence and wave-passage effects. There is no general trend about its effect on different components, whereas the system fragility increases as the soil conditions of adjacent excitation sites change more significantly and the soil types vary from the soft to the firm along wave-traveling direction. In addition, the bridge tends to be more vulnerable if the soil condition of the reference site becomes softer for the general excitation case. Spatial variability effects, especially incoherence and site-response effects, should be considered in the fragility analyses of this type of bridges.

scholarly journals Investigating the influence of topographic irregularities and two-dimensional effects on surface ground motion intensity with one- and two-dimensional analyses

2014 ◽  
Vol 14 (7) ◽  
pp. 1773-1788 ◽  
Author(s):  
G. Ç. İnce ◽  
L. Yılmazoğlu
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Soil Conditions ◽  
Response Analysis ◽  
Two Dimensional ◽  
Ground Acceleration ◽  
Equivalent Linear ◽  
Local Soil ◽  
Different Depths ◽  
Earthquake Response Analysis

Abstract. In this work, the surface ground motion that occurs during an earthquake in ground sections having different topographic forms has been examined with one and two dynamic site response analyses. One-dimensional analyses were undertaken using the Equivalent-Linear Earthquake Response Analysis (EERA) program based on the equivalent linear analysis principle and the Deepsoil program which is able to make both equivalent linear and nonlinear analyses and two-dimensional analyses using the Plaxis 8.2 software. The viscous damping parameters used in the dynamic site response analyses undertaken with the Plaxis 8.2 software were obtained using the DeepSoil program. In the dynamic site response analyses, the synthetic acceleration over a 475-year return period representing the earthquakes in Istanbul was used as the basis of the bedrock ground motion. The peak ground acceleration obtained different depths of soils and acceleration spectrum values have been compared. The surface topography and layer boundaries in the 5-5' cross section which cuts across the study area west to east were selected in order to examine the effect of the land topography and layer boundaries on the analysis results, and were flattened and compared with the actual status. The analysis results showed that the characteristics of the surface ground motion change in relation to the varying local soil conditions and land topography.

scholarly journals Effect of spatial variability of ground motion on non-linear dynamic behavior of cable stayed bridges

2018 ◽  
Vol 149 ◽  
pp. 02044
Author(s):  
Mouloud Ouanani ◽  
Boualem Tiliouine ◽  
Malek Hammoutene
Keyword(s):  
Spatial Variability ◽  
Dynamic Behavior ◽  
Ground Motion ◽  
Temporal Variations ◽  
Bridge Piers ◽  
Linear Dynamic ◽  
Cable Stayed Bridge ◽  
Non Linear ◽  
Bridge Responses ◽  
Cable Stayed Bridges

This present paper summarizes the main results of incoherence of Spatial Variability of Ground Motion (SVGM) component on the non-linear dynamic behavior of a Mila cable stayed bridge. The Hindy and Novack coherence model is developed for the present study in order to examine the SVGM on bridge responses, Nonlinear bridge responses are investigated in terms of transverse displacements and bending moments along the superstructure and substructure of the study bridge, as well as temporal variations of rotational ductility demands at the bridge piers ends under the incoherence SVGM component. The results are systematically compared with those obtained assuming uniform ground motion. As a general trend, it may be concluded that incoherence component of SVGM should be considered for the earthquake response assessments of cable-stayed bridges.

The basin effect and liquefaction in the catastrophe models: Case study – Vancouver region, Canada

2020 ◽  
Author(s):  
Svetlana Stripajova ◽  
Peter Pazak ◽  
Jan Vodicka ◽  
Goran Trendafiloski
Keyword(s):  
Ground Motion ◽  
Sedimentary Basin ◽  
Water Saturation ◽  
Site Response ◽  
Earthquake Ground Motion ◽  
Soil Conditions ◽  
Liquefaction Hazard ◽  
Geological Conditions ◽  
Catastrophe Models

<p>The presence of thick soft alluvial sediment-filled basins, like in river’s deltas, can significantly amplify and prolongate the earthquake ground motion. Moreover, the high-water saturation of such soft sediments and cyclic earthquake loading can lead to liquefaction. The basin and liquefaction effect can contribute to substantial modification of the seismic motion and increase of the potential losses at a particular location. Well-known examples of such high financial losses during earthquakes for basin effect is Mw 8.1 Mexico City 1985 and for liquefaction is Darfield and Christchurch earthquakes series in 2010 and 2011. Thus, the quantification of these effects is particularly important for the current underwriting products and the industry requires their further detailed consideration in the catastrophe models and pricing approaches. Impact Forecasting, Aon’s catastrophe model development center of excellence, has been committed to help (re)insurers on that matter.</p><p>This paper presents case study of the quantification of the basin effect and liquefaction for Vancouver region, Canada for specific scenario Mw 7.5 Strait of Georgia crustal earthquake. The southern part of the Vancouver region is located on a deep sedimentary basin created in the Fraser River delta. In case of deep Vancouver sedimentary basin considering amplification only due to shallow site response Vs30-dependent site term is not sufficient. Therefore, we derived (de)amplification function for different periods to quantify basin effect. We used NGA – West 2 ground motion prediction equations (GMPEs) for crustal events which include basin depth term. Amplification function was derived with respect to standard GMPEs for crustal events in western Canada. Amplification, considering site response including Vs30 and basin depth term at period 0.5 s can reach values as high as 3 at the softest and deepest sediments. The liquefaction potential was based on HAZUS and Zhu et al. (2017) methodologies calibrated to better reflect local geological conditions and liquefaction observations (Monahan et al. 2010, Clague 2002). We used USGS Vs30 data, enhanced by local seismic and geologic measurements, to characterize soil conditions, and topographical data and IF proprietary flow accumulation data to characterize water saturation. Liquefaction hazard is calculated in terms of probability of liquefaction occurrence and permanent ground deformation. For the chosen scenario the potential contribution to mean loss due to basin effect could be in the range 15% - 30% and 35% - 75% due to liquefaction depending on structural types of the buildings.</p>

Seismic Analysis of Structures Subjected to Spatially Varying Earthquake Using POD Vectors: Experimental and Analytical Studies

2020 ◽  
Vol 14 (04) ◽  
pp. 2050017
Author(s):  
K. Balamonica ◽  
N. Gopalakrishnan ◽  
A. Ramamohan Rao
Keyword(s):  
Seismic Analysis ◽  
Null Space ◽  
Time History ◽  
Soil Conditions ◽  
Classical Formulation ◽  
Local Soil ◽  
Wave Passage ◽  
Input Motion ◽  
Differential Excitation ◽  
Spatially Varying

Structures, such as bridges, pipelines which are supported at multiple places, will be subjected to differential excitation. A significant change in the correlation of the motions between the two supports is due to the combined effects of wave passage, coherency loss and local soil conditions. In the classical formulation, the response is divided into quasi-static and dynamic components and the latter is usually evaluated by time history methods or modal analysis for a linear system. In this work, the feasibility of Proper Orthogonal Decomposition (POD) vectors as a replacement for the conventional eigenvectors has been discussed. The performance of POD modes has been assessed for the uncoupled system, system having closely spaced modes. The null space vectors of the POD modes generated from the response of the structure subjected to correlated input motion were able to predict the responses of the structures subjected to spatially varying input motions. The efficiency of using the POD vectors has also been verified with the help of an experiment conducted on a steel control and safety rod drive mechanism (CSRDM) which is an example of multi-supported and differentially excited structure.

Earthquake Ground Motions: Implications for Designing Structures and Reconciling Structural Damage

1985 ◽  
Vol 1 (2) ◽  
pp. 239-270 ◽  
Author(s):  
Jogeshwar P. Singh
Keyword(s):  
Ground Motion ◽  
Strong Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Soil Condition ◽  
Dominant Factor ◽  
Soil Conditions ◽  
Earthquake Ground Motions ◽  
Geological Conditions ◽  
Strong Ground

Until recently, characteristics of strong ground motion resulting from different soil conditions were considered the dominant factor in developing design ground motions and reconciling observed damage. Interpretation of recent recordings of earthquakes by strong motion instrument arrays installed in California and Taiwan show that basic characteristics of strong motion are greatly influenced by the seismological and geological conditions. For a given soil condition, the characteristics of strong ground motion (peak ground acceleration, peak ground velocity, peak ground displacement, duration, spectral content, and time histories) can vary significantly whether the site is near or far from the seismic source. As local soil conditions only modify the ground motions produced by a given source, variability in ground motion due to seismologic and geologic conditions (for a given soil condition) must be considered in estimating earthquake ground motions for structural design or for estimating structural vulnerabilities to reconcile earthquake-related damage.

scholarly journals Investigation of the influence of topographic irregularities and two dimensional effects on the intensity of surface ground motion with one- and two-dimensional analyses

2013 ◽  
Vol 1 (6) ◽  
pp. 7193-7238
Author(s):  
L. Yılmazoğlu ◽  
G. Ç. İnce
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Soil Conditions ◽  
Response Analysis ◽  
Two Dimensional ◽  
Ground Acceleration ◽  
Equivalent Linear ◽  
Local Soil ◽  
Different Depths ◽  
Earthquake Response Analysis

Abstract. In this work, the surface ground motion that occurs during an earthquake in ground sections having different topographic forms has been examined with one and two dynamic site response analyses. One-dimensional analyses were undertaken using the Equivalent-Linear Earthquake Response Analysis program based on the equivalent linear analysis principle and the Deepsoil program which is able to make both equivalent linear and nonlinear analyses and two-dimensional analyses using the Plaxis software. The viscous damping parameters used in the dynamic site response analyses undertaken with the Plaxis software were obtained using the DeepSoil program. In the dynamic site response analyses, the synthetic acceleration over a 475 yr replication period representing the earthquakes in Istanbul was used as the basis of the bedrock ground motion. The peak ground acceleration obtained different depths of soils and acceleration spectrum values have been compared. The surface topography and layer boundaries in the 5-5' section were selected in order to examine the effect of the land topography and layer boundaries on the analysis results were flattened and compared with the actual status. The analysis results showed that the characteristics of the surface ground motion changes in relation to the varying local soil conditions and land topography.

scholarly journals Running safety assessment of a train traversing a three-tower cable-stayed bridge under spatially varying ground motion

2020 ◽  
Vol 28 (2) ◽  
pp. 184-198 ◽  
Author(s):  
Wei Gong ◽  
Zhihui Zhu ◽  
Yu Liu ◽  
Ruitao Liu ◽  
Yongjiu Tang ◽  
...  
Keyword(s):  
Ground Motion ◽  
Safety Assessment ◽  
Running Safety ◽  
Cable Stayed Bridge ◽  
Spatially Varying
Sign in / Sign up

Export Citation Format

Share Document